The proposed research will broaden previous investigations of mental retardation in a traditional residential institution to include a variety of alternative residential settings in four states, representing different patterns of care. The research is based on a model in which characteristics of retarded individuals and their families are seen to interact with characteristics of residential settings to produce differential outcomes, notably changes in developmental status. Five interrelated projects are proposed, each of which has its own specific aims, methods of procedure, and significance. All of them relate to the basic model, and all have as their ultimate objective the discovery of ways to improve retarded individuals' adaptation to their environments.